The present invention relates to a wheel hub; more particularly to provide a process for manufacturing a wheel hub for vehicles, such as bicycles.
Accordingly, the hubs are located at the front and rear wheel axles. When vehicle is in motion, all shocks and vibrations are transimitted to the frame through the hubs. Moreover, the motivating power to move the vehicle is transmitted as torque, pressure, extension and shear through to the drive wheel. Therefore, the hub is an extremely important component of a vehicle such as bicycle. Take a front hub as an example, please referring to FIG. 1.
The conventional hub 10 comprises an axle tube 11 and two hub flanges 12 which respectively include a bearing receiving bowl 13. The hollow cylindrical axle tube 11, has two axial opening ends. Each bearing receiving bowl 13 has a weld portion 131 adjacent to its axial hole which diameter subtantially equals to the diameter of both ends of the axle tube 11. And each hub flange 12 and bearing receiving bowl 13 is single piece constructed and formed by pressing. With the two axial holes of the two bearing receiving bowls 13 respective to both ends of the axle tube 11, both ends of the axle tube 11 are respectively connected with the weld portions 131 of the two hub flanges 12 and the two bearing receiving bowls 13 by welding. However, the disadvantages of the welding connection are:
1. the connected portion of the axle tube 11, the hub flange 12 and the bearing receiving bowl 13 will be split open, because the welded portion is so close to the concentric axis that the welded portion cannot resist the high torque;
2. welding costs too much in manufacturing;
3. the conventional hub flange 12 and bearing receiving bowl 13 need five steps of stamping, then make its axial hole;
4. although only the bearing receiving bowl 13 needs heat treatment, the conventional hub flange 12 and bearing receiving bowl 13 and the axle tube 11 are made of a single iron plate and manufactured by stamping press, they will have heat treatment together; therefore it raises the manufacturing cost again.